1. Technical Field
The following description relates to one or more document feeders provided to an image forming device.
2. Related Art
Japanese Patent Provisional Publication No. 2007-51005 (hereinafter referred to as '005 Publication) discloses an automatic document feeder, which is applied to an image forming device having a scanner unit and provided with a tray having a loading surface on which a document is placed.
Further, the automatic document feeder is provided with a spindle, holder, paper feed roller, and separation roller so as to supply the document on the loading surface to the scanner unit on a sheet-by-sheet basis (see FIG. 2 of '005 Publication).
The spindle is provided to extend, above the tray, in a direction that is parallel to the loading surface and perpendicular to a carrying direction in which the document is conveyed, and to be rotated to carry the document. The holder is swingably provided to the spindle. The paper feed roller is rotatably provided to the holder at an upstream side in the carrying direction so as to be driven in accordance with the rotation of the spindle. The separation roller is provided at a downstream side in the carrying direction within the holder so as to be rotated integrally with the spindle.
Further, the automatic document feeder includes a detecting unit configured to detect whether a document is placed in the tray (see FIGS. 2 to 4 of '005 Publication). Specifically, the detecting unit has an actuator protruding upward from the tray in a position away from the paper feed roller obliquely toward an upstream side in the carrying direction. The actuator is swingably supported at a backside of the loading surface so as to be moved owing to contact with the document on the loading surface. The detecting unit checks whether a document is placed in the tray by detecting, with a sensor, the downward movement of the actuator caused by the weight of the document in the tray.
The automatic document feeder configured as above checks with the detecting unit whether a document is placed in the tray, when receiving an instruction to supply the document to the scanner. When detecting the document placed in the tray, the aforementioned automatic document feeder causes the spindle, paper feed roller, and separation roller to rotate and feeds the document to the scanner on a sheet-by-sheet basis.